Regulation light beams produced by motor vehicle headlights are not generally well adapted to travelling round a bend, because they are oriented in a manner which is fixed and generally directed longitudinally forward. But when the vehicle is passing round a bend, the driver ideally needs lighting which is directed preferentially into the bend, so that the bend itself is properly illuminated and he is enabled to anticipate the remainder of the bend and can more readily put the vehicle in its best path.
There are, in the main, three known solutions for producing light beams which are specifically adapted for negotiating bends.
One solution to this problem which is already known makes use of the passing headlights of the vehicle, in that they are mounted for pivoting movement to follow the direction of the bend. For example, in a left hand bend, the left passing headlight pivots to the left, and in a right hand bend, the right hand passing light pivots to the right. This arrangement is not satisfactory, because, in order to mount a passing headlight pivotally, the characteristics of the cutoff in the regulation dipped beam are modified, and in particular the distribution of light intensity around the cutoff. This makes it difficult to ensure that the lighting apparatus continues to comply with current applicable law.
Another known arrangement involves the use of small additional driving lights, for example the foglight module. These additional lights are oriented in the direction of the bend as a function of the angle of rotation of the steering wheel and the forward speed of the vehicle.
In a third known type of solution, two small additional driving lights are used, each of which is pre-oriented to one side of the longitudinal axis of the vehicle. The right and left additional lights are for example oriented in two horizontal directions which describe an angle of 45°, to the left and the right respectively, with respect to the longitudinal axis of the vehicle. The light intensity produced by these additional lights may be controlled as a function of the angle of rotation of the steering wheel and the forward speed of the vehicle, as in the previous example.
These last two known arrangements make it necessary to provide an additional lighting module. In addition, the light flux produced by the additional lights is quite small.